Throughout history, various nations, societies and civilizations in numerous epochs have endeavored to produce devices of protection and convenience for the sole purpose of preventing the accumulation of adherent moisture associated with the use of drinks and liquids contained in moisture-bearing vessels, utensils and containers which were at temperatures lower than the dew point of the environment. Indeed, even Greek mythology mentions the inconvenience of unabsorbed moisture encountered by the Hellenic deities as they consumed their various libations on the heights of Olympus. And today it is common to see inconvenienced bar patrons struggle with coasters which do not adequately dispose of adherent moisture and which cling to glasses, cans, bottles and any other containers bearing or producing condensation and, subsequently, leaving potentially damaging moisture on surfaces.
The most common coasters are characterized by a one-layer construction of absorbent material composed of cork, wood or paper fiber or cotton; and which, when overladen or saturated with moisture, no longer suffice to provide a damp-proof, protective device. To the contrary, such coasters ultimately permit an adhesive seal, which joins the coasters to the containers.
Subsequent improvements of the art in the modern era have witnessed numerous attempts to cope with the problem of attendant moisture coming into contact with and damaging finished surfaces.
An improvement of the coaster art occurred with U.S. Pat. No. 3,363,869 (Blundell). In this folding unit, a napkin or other absorbent material was placed into the interior, while a lattice top (once folded over the napkin or absorbent material) provided a degree of aeration to assist in the disposal of condensation. Although representing an advance in the art, the device still presented some obvious difficulties: (1) the inconvenience of the periodic disposal of a saturated napkin or other absorbent material; and (2) the presence of a retaining well, which would demand recurring emptying and/or attention to condensation on the exterior of the rim.
Prior to Blundell, U.S. Pat. No. 2,688,858 (Cosmetto) sought to combine the functions of absorbency and aeration in a circular coaster of low-cost plastic molding, including a top of relatively large interlocking and circular grills, under which lay a slot for removal and replacement of saturated absorbent blotters, surrounded by a plastic, circular supporting frame. It was assumed that the large circular grills would dispense with major amounts of condensation, while what remained of the moisture would be absorbed by the disposable blotters. Although the factor of aeration represented by the large circular grills was a positive development, the inconvenience of disposal of a saturated absorber was not, significantly, dealt with, and the close proximity of the blotter to supporting surfaces held great potential for damage to those surfaces. Also, the relatively large size of the supporting grills made it more likely that large amounts of moisture would be channeled into the replaceable absorbent material, which was positioned at the base of the coaster and directly on furniture and other supporting surfaces.
U.S. Pat. No. 4,858,872 (Witt) describes a coaster for supporting glasses and other containers which includes a tray which is mounted in spaced vertical relationship with respect to a base element in such a manner that an open air space is created therebetween. The tray is provided with a plurality of drain openings which communicate with an absorbent pad or wick material which is mounted beneath or suspended from the tray so as to receive condensation and other moisture passing through the drain openings. Nevertheless, the coaster of this patent is characterized by several disadvantages, to wit: (1) the expense and inconvenience of the possible necessity of replacing spoiled absorbent material and holding trays; (2) the coaster, as described in its various forms, could be expensive and laborious to produce and could not fulfill the needs of a mass market; (3) regular vigilance is demanded in order to prevent spillage from the attached tray and to determine if an absorbent pad is in need of replacement; (4) as disclosed in accompanying illustrative drawings of this invention, the "annular channels" do not seem of sufficient dimension to guarantee the direction of moisture in a downward path through the device and, ultimately, into the tray; and (5) the wick elements, if included in the embodiment which provides for direct contact with the condensation basin, risk becoming noxious conductors of resultant odors from deterioration byproducts or the possible accumulation of mildew or other mold.
It would be desirable if a cling resistant drink coaster could be devised which would overcome many of the disadvantages of prior coasters.